Dressing mechanism for grinding wheels



June 13, 1944- G. STEWART 2,351,159

DRESSING MECHANISM FOR GRINDING WHEELS Filed OCt. 17, 1941 4 Sheets-Sheet 1 June 13, 944.

G. STEWART DRESSING MECHANISM FOR GRINDNG WHEELS 4 shets-snet 2 jizz/@rz nf' Glerf Siga/arf- Fled Oct. 17, 1941 June i3, i944. @STEWART DRESSING MECHANISM FOR GRINDING WHEELS Filed Oct. 17, 1941 4 Sheets-Sheet 3 june 13, 1944. Y y STEWART 2,351,159

DRESSING MECHANISM FOR GRINDING WHEELS Filed Oct. 17, 1941 4 Sheets-Sheet 4 \\N l' IIIIIH 55a 56 y \\yirnvlplnn,;y\ 4d 4'1 i v 4. K

Patented June -l3, 1944 Gilbert Stewart, Detroit, Mich., assignor to Ex- Cell-O Corporation. Detroit. Mich.. a corporation oi Michigan Application october 11,1941, serial No, 415,313

s claims. (ci. 12s-11) 'I'he present invention relates to a dressing mechanism for grinding wheels, and has particular reference to a new and improved mechanism in which a single dressing tool is arranged for power oscillation to generate a 4contour of non-arcuate form. I

One'of the objects of theinvention is to provide a novel dressing mechanism of the foregoing character in which -a unidirectional powerdrive is employed for swinging the dressing tool, and in which a cam of preselected shape is operative to modify the path of'movement of the tool so as to generate a contour of desired form on the grinding wheel.

Another object is to provide a dressing mechanism of the foregoing character comprising novel means for effecting dimensional adjustments of the dressing tool.

Other objects and advantages will become apparent as the description proceeds.

In the accompanying drawings: i

Figure 1 is a fragmentary vertical .sectional view of a. dressing mechanism embodying the features of my invention.

Fig. 2 is an end elevational viewof the dressing mechanism.

Fig. 3 is a plan viewof the dressing mecha- CTI predeteminedrelation to the grinding wheel W.

Mounted on the base 3, for angular adjustment abouta horizontal axis l perpendicular to and intersecting the axis 5 of the spindle I in the medial transverse plane 6 of the grinding wheel W, is a swivel plate 1 for supporting the dressing tool assembly. More particularly, the swivel plate -1 is supported on a xed bearing stud 8 fitted into the body 3 and secured in position by a bolt 9. The plate I is formed about the periphery with spaced arcuate slots I0 through which clamping bolts II extend into threaded engagement with the base 3. An indicator i2 is provided for showing the degree of angular adl l erally vertical bore I5 extending transversely of the swivel axis. A shaft I6 is suitably journaled in spaced ball bearings II within'the bore I5,

nism partially insection along the line 3--3 of Fig. 1.

Fig. 4 is a fragmentary vertical sectional view taken along line 4--4 of Fig. 1.

Fig. 5 is a fragmentary view partially in side 'elevation and partially in section along line 5 5 of Fig. 4.

Fig. 6 is a diagrammaticrepresentation illustrating the controlled' path of movement of the 1ar1y 'for grinding internal threads. The grind-l ing machine forms no part of the present invention, and hence' ls not shown in detail. The grinding wheel W is mounted on a spindle I suitably journaled in a bracket 2 which is supported by means (not'shown) for angular ad-` justmentto incline the grinding wheel in accordance with the lead of the thread to be` ground.

The dressing mechanism comprise-sa base 3 adapted to be vmounted on a suitable support in and at its lower end supports a dressing tool assembly I8 for swinging or oscillatory movement. In the present. instance, the shaft I6 is provided with' a diametrical cross head i9 formed with plementary guideway 22, is adjustably mounted on the guide 20 and is formed with a depending bracket arm 23.

Adjustably secured to the arm 23 is a block l 24 for supporting the dressing tool T. The block 24 is positioned on the arm 23 by a tongue 25 and groove 26, and is adapted to be secured in position by means of a clamp bolt 21 extending through an elongated slot 28 in the arm.- A pin 2s projects from the arm 23 across the forward end of the block 24, and definitely locates the latter in relation to the axis of oscillation.

The dressing tool T is mounted in the end of a shank 30 extending adjustably into an inclined bore or socket 3I in the lower end of the block 24, and adapted to be secured in position by a set screw 32. An adjusting screw 33 is threaded into the rear end of the bore 3| in end abutment with the tool shankv 30 to locate and back up the latter.

It is to be understood that, to a certain degree, the attrition ofthe dressing tool T ,which results` from contact with the grinding wheel W may be .estimated andeompensated by adjustment of screw 33 thus maintaining the effective point of the tool at a predetermined radial position location of the` diamond tool T in relation to the block 24 may be determined and the desired adjusted position may be accomplished by screw 33.

In practice it is customary to have a multiplicity of blocks 24 with their associated dressing tools available in correctly adjusted relationship ready for interchangeable use on the bracket 2| without altering the form which is dressed upon wheel W. In the alternative use of such blocks 24 the pin 29 together with tongue 25 and groove 26 determines the correct location of block 24 with respect to bracket 2|.

Oscillation of the shaft I3 serves to swing the dressing tool T in a normallyarcuate path. Cam means is provided for modifying the path of swinging movement in order to provide the grinding wheel with a non-arcuate .contour of any particular form. To this end, a curved template or cam 34 is removably secured about the lower end of the sleeve I4. The cam 34 has an inner arcuate face concentric with the axis of the shaft |6 and permitting rotary adjustment and an outer conflgurated cam face 33 which .may be non-arcuate. the cam 34 may be effected by means of screws 35, and suitable bolts 35a extending slots 35h are provided of adjustment. A cam follower 31 engages the cam face 36, and is fixed on the rear end of a plunger 38 slidable in a bore 39 opening longitudinally through the cross head I9. The forward end f the plunger. is attached to the tool slide 2| and has a reduced portion 40. A coiled compression. spring 4| encircles the reduced portion 40 within the bore 39 and through. for securing the cam in' The motor is controlled by, a switch 56 mounted on the base 3 and having a control lever 51 normally biased toward the periphery of a cam 5B Il xed on the outer end of the shaft 5|. The cam 53 has a peripheral lug 59 adapted at the end of each revolution to depress the lever 51, and thereby stop the electric drive motor at the end of each dressing cycle.

It will be seen that the cam 43 by reason of the groove 45 will'in one revolution oscillate the shaft IB back and forth through its full range of movement, and hence a simple unidirectional drive for the shaft 55 can be employed.

I claim:

1. A dressing mechanism comprising, in combination, a base, a swivel plate mounted for an gular adjustment on said base, a bracket on said swivel plate. a rock shaft on said bracket and extending perpendicularly to the swivel axis, a dressing tool holder mounted on one end of said rock shaft and adapted to be oscillated thereby, said holder supporting a dressing tool for adjustment radially of the shaft axis, a rotary cam journaled in said bracket and having a continuqus spira-l cam groove, means coacting with said groove and operatively connected to said shaft to oscillate the latter back and forth for each complete revolution of said cam, and a worm and worm wheel drive for said cam.

2. A dressing mechanism comprising, in combination, a base, a swivel plate mounted for angular adjustment on said base. a bracket on Adjustment of through end abutment with an internal `nange 42 serves to urge the slide 2| forwardly and hence to hold the follower 31 in engagement with the cam face 36. Consequently, as the shaft I3 is rocked through approximately 180 to oscillate the dressing tool "I', the cam 34 will cause the dressing tool slide to 4shift in timed relation so as to generate a non-circular path of cut as indicated in Fig. 6.

To provide means for oscillating the shaft I3. a rotary cam drum 43 is journaled in a'bore 44 inthe bracket I3 for rotation on an axis parallel to the swivel axis 4 of the plate 1. The cam drum has a continuous spiral groove 45 formed in its periphery. A bar '43 is slidable in a'longitudinal groove 41 in one side of the bracket |3,and carries a roller 48 in engagement with Y the groove 45. The forward end of the bar 4,3 is formed with a gear rack 49 meshing with a pinion 50 on the rock shaft I6..

' The cam drum 43 is rigid with an axial shaft 5| which extends through a gear housing 52 on the rear end of the bracket I3. A wormwheel 53 is keyed to the shaft 5| within the gear housing 52 and meshes with a worm 54 on a drive shaft 55 projecting from the housing for connection to a suitable source of power, such as an electric motor (notshown).

said swivel plate, a rock shaft` on said bracket and extending perpendicularly to the swivel axis, a dressing tool holder mounted on one end of said rock shaft and adapted to be oscillated thereby, a rotary cam journaled in said bracket and having a continuous spiral cam groove, means coacting. with said groove and operatively connected to said shaft to oscillate the latter back and. forth for each complete revolution o f said cam, and means for rotating said cam in one direction. Y

3. A dressing mechanism comprising, in combination, a base, a swivel plate mounted on said base for angular adjustment to different selectedy positions and having an eccentricallly disposed bracket. a bearing sleeve on one end of said Ibracket, a shaft journaled in said bearing sleeve for rotation on an axis perpendicular to the axis of said swivel plate and supporting a transverse guide. a curved cam partially circumscribing said bearing sleeve. a dresser slide reciprocable on said guide, a follower connected to said slide for movement therewith and coacting with said cam, spring means acting on said slide to maintain said follower in contact with said cam, a block removably mounted -on said slide, a dressing tool adjustably mounted on said block, stop means for locating said block in predetermined position on said slide, and means on said bracket for oscillating said shaft, said cam acting to modify the swinging movement of said dressing tool so as to cause the Ilatter to'describe a predetermined non-arcuate path of movement.

4. A dressing mechanism comprising, in combination. a base. a swivel plate mounted for anguiar adjustment on said base, a bracket on said swivel plate, a rock shaft on said bracket and extending perpendicularly to the swivel axis, a dressing tool holder mounted on one end of said rock shaft and adapted to be oscillated thereby, a dressing tool mounted on said holder for adjustment radially of the shaft axis, means acting automatically to control the radial position of said tool on said holder in different positions of oscillation of said holder, a rotary cam journaled in said bracket and having a continuous spiral cam groove, means coacting with said groove and operatively connected to said shaft to oscillate the flatter back and forth for each complete revolution of said cam, and means for rotating said cam in one direction. v

5. A dressing mechanism comprising, in combination, a base, a swivel plate mounted for angular adjustment on said base, a bracket on said swivel plate, a rock shaft on said bracket and extending pcrpendicularly to the swivel axis, a dressing tool holder mounted on one .end of said rock shaft and adapted to be oscillated thereby, a dressing tool mounted on said holder for adjustment radially of the shaft axis, a curved cam member partially circumscribing said axis and formed with a conngurated cam face along its length, a cam follower coacting with said tool, spring means for maintains said follower in engagement with said cam face, said follower coacting with said cam face to control the radial .position of said tool on said holder in different positions of oscillation of said holder, a rotary lcam iournaled in said bracket'and having a continuous spiral cam groove, means coacting with said groove and operatively connected to said shaft to oscillate the latter backand forth for each complete revolution-of said cam, and means for rotating said cumin one direction.

GILBERT STEWART. 

